Trudy GAISH, vol. LXV, 1996
The global distribution of average (5Ox5O) depths
of Mohorovicic discontinuity on the Earth
by P.A.Stroev, E.D.Koryakin, A.N.Groushinsky
The available seismic data for the thickness of the earth crust were compiled and averaged on the 5Ox 5O grid for the whole Earth. For any distant and inaccessible, and by this reason poorly known, regions, such as high mountains of the Middle, South and Little Asia, American Cordilleras and Andes, Antarctica, Greenland and so on, these data are absent. So, for such regions the depths of Moho discontinuity was estimated by means of the correlation between the thickness of the crust, topography and Bouguer anomalies. For each cell of the grid the depth of Moho discontinuity was determined by averaging of all data, existing in this cell. In the cartography grid of the Earth, there are 2592 cells. The cells, which contain data for the thickness of the earth crust, cover approximately 80% of the Earth surface. The summary of these cells is presented. The resulting map of the Moho discontinuity depths with the isoline interval equal to 5 km is drawing. The reliability of the resulting data was estimated.

A Spherical Harmonic and Statistical Analysis
of the Moho Surface (M) Depths
by N.A. Chujkova, T.G.Maximova
The Moho surface (M) depths are expanded in terms of a spherical function system up to the degree N = 30. The statistical analysis of the expansion carries on to the following principal conclusions:

1) The average M depth is 22.37± 0.20 km.

2) The displacement of the M figure center from the Earth center is 9.31 km in the direction: the latitude = -39.9 degrees, the longitude = 230.9 degrees.

3) The polar M flattening is 0.0053, the equatorial one is 0.0015. They considerably exceed the geoid flattenings (0.00335 and 0.00001).

4) The principal features of M relief are represented in the 9 degree expancion.

The maps of the M depths (relative to geoid) and of the M altitudes (relative to the hydrostatic figure) are obtained and analysed for N = 30,9,5. The reliability of the resulting data is estimated.

The Spherical Harmonic and Statistical Analysis of the
Earth Equivalent Rock and its Isostatic Compensation
by N.A.Chujkova, A.N.Grushinsky, T.G.Maximova
The equivalent rock topography r is represented as the spherical function expansion up to degree 30. That expansion is compared to the Moho surface expansion and to the gravity field of the Earth. The principal results are:

1) the mean radius of r is 6369.62 km;

2) the r figure center is displaced from the Earth center at the distance of 1.04 km in the direction ;

3) the polar r flattening is 0.00329, the equatorial one is 0.00017;

4) isostatic compensation of topography exists on the depths less then M depths for degree more or equal 3, and deeper for degree equal 1 and 2;

5) the difference between the geoid flattenings and the r and hydrostatic flattenings is caused by the large M flattenings;

6) the estimation of the Moho depths by means of the correlation with the Bouguer anomalies are not confirmed. The estimation on the basis of the isostatic compensation hypothesis is possible only for large-scale Moho extension, which are characterized by the expansion of 10 degree and less.

The search of sources of the gravity anomalies
by S.A.Kazaryan
The interpretation of sources of the anomalies of the Earth's gravity field is carried out. The point sources were placed under the largest geoid's anomalies. Their coordinates, masses and limit depths of the location are determined. Such analysis allows detecting whether the sources of the largest anomalies reside within the Earth's core. This is possible if the limit depths of the sources exceed the depths of the core-mantle boundary.  
The Earth core's internal structure as a total source of gravity and magnetic fields anomalies: preliminary results
by N.A.Chujkova, N.V.Alakverdova
The problem of the search of the correlative dependence between the gravity and magnetic anomalies is investigated. This dependence should exist if gravity and magnetic fields have common sources of the different shape and origin, laying in the outer core.

The formulas of gravity and magnetic potentials of such sources are received. The original method of search of correlative dependence for the sources, laying in the common axis is worked out. The method is tested using the concrete models of Earth gravity and magnetic fields, base on the observations.

On the Earth's Inner Core Dynamics
by Yu.V.Barkin
The differential equations of the inner core motion in liquid core of the Earth under attraction of the mantle and Moon and Sun have been obtained. These equations were reduced to the equations with conditionally-periodic coefficients. The frequencies of the inner core librations and phenomenon of the constant displacement of the center mass of the rigid core are investigated. Secular and periodic perturbations in the inner core motion due to main geophysical processes have been studied.

On the polar free oscilation of the Earth’s Inner Core
by Pasinok S.L.
 Influence of the Earth’s cover on the polar free oscillation of the Earth’s inner core is considered. Two cases of the Earth’s cover were studied , corresponding frequencies are calculated.

Dependence of the reversals frequency of geomagnetic field
on the position of Solar system in the Galaxy
by N.A. Chujkova, K.V. Semenkov
The problem of the Sun’s motion in the Galaxy is solved, the Sun’s orbit for a modern model of Galaxy potential is calculated. Fourier-analysis of time dependence of geomagnetic reversals frequency for 550 million years is made. Next regularities are revealed by comparing palaeomagnetical data with Sun’s position in the Galaxy: the frequency of geomagnetic reversals is a maximum when the Sun’s system cross such Galaxy’ regions where the gravity potential and ambient physical characteristics are varied to the utmost, namely, when the Sun leaves the Galaxy’ spiral arms, the Sun cuts across the Galaxy disk, the Sun is at the minimal distance from the Galaxy centre.

To specify received regularities and to find out their causes further investigations are needed.

The mass and the moment of inertia of the Earth
 by V.E.Zharov
There are the discrepancies between the observed and theoretical amplitudes of the nutation terms. One of possible explanations of this is the application of the simplified model of the Earth consisting from the elastic mantle, liquid outer core and elastic inner core. More complex model have to be considered. One of more complex model of the Earth has been proposed by Chujkova and Maksimova [1]. The main conclusion is that the Mohorovichich surface's ellipticity is greater than that of the crust and the center of ellipsoid has bias from the center of Earth's mass. The estimation of the mass and the moment of inertia of the Earth with new model of Moho surface and biased inner core has shown that our result is consistent with the common values. So this model can be used for further investigation.